How high can wall units be stacked before placing unit corefill and backfill?
Because of the difference in depth and size of open core areas, most standard wall units can be stacked up to a maximum of 3 units before placing unit corefill and backfill. Adding backfill after each consecutive course insures that all voids are properly filled with rock providing maximum interlocking strength. It also aids in keeping the wall straight and reduces the amount of wasted rock.
